The present disclosure relates to a semiconductor device having a configuration in which semiconductor substrates are bonded to each other and a method of manufacturing a semiconductor device.
A process of manufacturing a semiconductor device such as an image sensor includes a process of bonding a semiconductor substrate in which an imaging device is formed to another semiconductor substrate, a glass substrate or the like. In the process of bonding substrates, semiconductor substrates are bonded to each other using plasma bonding or an adhesive.
On the other hand, a warpage may be generated in a semiconductor substrate due to the stress difference between an insulating layer, a wiring line or the like formed on a semiconductor substrate and the semiconductor substrate. When a warpage is generated in semiconductor substrates to be bonded, the bonding accuracy is lowered in the above-mentioned bonding process. For this reason, in order to realize high-accuracy bonding, it is necessary to correct a warpage of a semiconductor substrate.
In bonding between a semiconductor substrate and a glass substrate, a method is proposed in which a warpage is corrected by forming a groove in the glass substrate and reducing the stress difference between the glass substrate and a thin film formed in the glass substrate (see Japanese Unexamined Patent Application Publication No. 2006-282480).